Rooms for Transformers

[mshields]

For electric rooms with transformers greater than 112.3 KVA you need to be in a 1 hour rated room correct. How about in an industrial facility where they customer wants to put in substation. Does this same ruile apply. Are there exceptions for Industrial factory floors?

 

[ron]

I'm not aware of a 1 hour rated room requirement with current day specified transformers.

 

[Charged]

To clarify what Ron mentioned, this is from Hammond power solution website

A 1 hour fire separation barrier is required for any dry type transformer over 112.5 kVA with less than class 155C insulation. As a practical matter, few dry type transformers in this size range utilize insulation systems below 155C. The most common insulation type is 220C

I’ve been incorrectly applying this section myself.

 

[Besoeker3]

For electric rooms with transformers greater than 112.3 KVA you need to be in a 1 hour rated room correct. How about in an industrial facility where they customer wants to put in substation. Does this same ruile apply. Are there exceptions for Industrial factory floors?

FWIW we always located our transformers outside.

 

[petersonra]

FWIW we always located our transformers outside.

Generally a good idea if you can find a spot close by. No reason to use valuable floor space with something that can be outside, especially something that generates heat like a transformer.

 

[Besoeker3]

Generally a good idea if you can find a spot close by. No reason to use valuable floor space with something that can be outside, especially something that generates heat like a transformer.

The problem is that they are oil-filled so puting them inside is a bit of a problem. That said, we did have a few inside with a large tank in case there was an oil spillage. These were a bit special - the low voltage side was 40,000A rectifiers.

 

[augie47]

The Code Section he mentioned (over 112.5) references dry type transformers so we assumed it was not oil filled. True that would be a whole different ballgame.

 

[ron]

FWIW we always located our transformers outside.

I'm thinking he meant 112.5kVA dry.

BTW, with XFMR efficiencies so high now a days, we save a lot of copper for only a little HVAC expended by putting our seed oil filled transformers (FR3) indoors too when the transformers get large.

 

[Besoeker3]

The Code Section he mentioned (over 112.5) references dry type transformers so we assumed it was not oil filled. True that would be a whole different ballgame.

Yes, I agree. The original poster mentioned industrial factories which is what I commented on.

 

[mshields]

Great input as always gentlemen. And it makes me realize something else I am apparently confusing. That insulation rating is not the same as the temperature rise ratings of 80, 115 or 150. Who different thing right?

 

[mshields]

I did mean dry incidentally

 

[jim dungar]

Great input as always gentlemen. And it makes me realize something else I am apparently confusing. That insulation rating is not the same as the temperature rise ratings of 80, 115 or 150. Who different thing right?

Correct. Insulation rating is not the temperature rise of the unit.

Insulation is usually something like Class H for 150 degrees.